Improvement in locks for sewing-machine covers



' UNITED STATES PATENT OFFICE.

JOHN B. LOGAN, OF BALTIMORE, MARYLAND.

IMPROVEMENT IN LOCKS FOR SEWING-MACHINE COVERS, &c.

Specification forming part of Letters Patent No. 170.575, dated November 30,1875; application filed April 30, 1875.

To all whom it may concern Be it known that I, J OHN B. LOGAN, of Baltimore, in the county of Baltimore and State of Maryland, have invented certain new and useful Improvements in Locks; and do hereby declare that the following is afull, clear,-and exact description thereof, that will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming a part of this specification, in Which Figure 1. shows a plan of my lock. Fig. 2 shows the lock with the face-plate removed; Fig. 3, section through a 1).

Same letters show like parts.

My lock combines simplicity, durability, and economy in its construction. It is particularly adapted for use upon sewing-machines, as a means of securing the cover of the machine to the table; but is applicable to many other purposes. It consists of five parts only, viz, front and back plates, bolt, cam, and attaching-screw, which not only secures the lock in position, but also holds its parts together, serves as a pivot for the bolt to turn upon, and as a means of regulating the action of the bolt, the ease of which may be increased or diminished by tightening or loosening the central screw.

Referring to the drawings, a shows the back plate of the lock, shown as having a flange, b, at its periphery, forming the edge of the lock-case. One or more projections, 0, may be made on the under side of this plate, to keep it in position when applied. At d is the bolt, pivoted at or near the center of the lock, forming a lever, engaging the staple j at its upper end, and at its lower end 0 engaging a cam, f, by which it is operated. This cam has hearings in the front and back plates of the lock, upon which it turns, and is provided with a keyhole, g, by which it 'is rotated to throw the lever-bolt d. At. It is shown the front plate of the lock, which also forms its escutcheon. An opening, 6, is made through both plates at and h, through which the staple j passes, and the flange 1) (before referred to) may, of course, be attached to either plate, as preferred. At 70 is shown a screw, passing through both plates at and h, the lever-bolt,

and into the article upon which the lock is used. This, as before stated, secures the lock to the article, holds its parts together, and

serves as a pivot for the bolt. The head ofthis screw not only has a bearing upon the plate h, but also a slight bearing upon the bolt d,-so that as it is tightened said bolt is pressed downward upon the bottom plate a. This enables .the action of the bolt to be regulated by increasing or diminishing the friction between the parts, and obviates the necessity of using springs.

My lock may be applied by inserting it in the article upon which it is-used, so that their surfaces shall be flush; or it may be placed upon or above its surface; or its escutcheon or front plate h only may project, the manner of application depending on the purpose for which it is used. Its operation is simple and apparent.

Ido not claim the devices shown in the patents of James Jones, September 3, 1846, nor William Patton, September 8, 1857, for sash holders and fasteners. My invention differs from these both in its construction and object. It relates to that class of locks in which the operative parts are inclosed in a lock-case, which caseis, in myinventioinformed by the escutcheon and back plate. It is especially designed for application to sewing-machines and like purposes, whereit is desired to unite elegance of finish with economy of construction.

What I claim as my invention, and desire to secure by Letters Patent, is' v In a lock, the combination of the back plate a and escutcheon-plate h, forming the lockcase, with the lever-bolt d, cam f, and screw 76, said screw forming the pivot of the lockbolt, uniting and holding in position the parts of the lock, securing it to the article upon which it is used, and regulating the action'of the bolt, substantially as specified.

In testimony that I claim the foregoing I have hereunto set my hand this 23d day of April, 1875.

JOHN B. LOGAN.

Witnesses:

J OHN M. TUCKER, HENRY B. HICKS. 

